Patrick,
BWG hit the nail on the head. The heart of the difference is eternal security or Once Saved Always Saved. In Catholic theology works do not save in that they do not bring us grace, but grace needs to result in works. Grace is the food we recieve. Baptism and the Eucharist that provide us the "energy" to do good. But grace is not irresistable and therefore if we do not complete the grace in the works our spiritual bodies become lazy and we begin to slide. Virtue (i.e. chairty, etc.) counters vice. If we are doing good in our lives we are not sinning and sin makes us weak and will eventually enslave us. God works, i.e. practicing virtue is the excercise for our spiritual bodies, like lifting weights or running to our physical bodies.
As for ES or OSAS there are many passages that refute them. This is what was read at Mass yesterday:
"I am the vine, and My Father is the
vinedresser. [2] Every branch of mine that bears no fruit, He takes
away, and every branch that does bear fruit He prunes that it may bear
more fruit. [3] You are already made clean by the word which I have
spoken to you. [4] Abide in Me, and I in you. As the branch cannot
bear fruit by itself, unless it abides in the vine, neither can you,
unless you abide in Me. [5] I am the vine, you are the branches. He
who abides in Me, and I in him, he it is that bears much fruit, for
apart from Me you can do nothing. [6] If a man does not abide in Me,
he is cast forth as a branch and withers; and the branches are
gathered, thrown into the fire and burned. [7] If you abide in Me, and
My words abide in you, ask whatever you will, and it shall be done for
you. [8] By this My Father is glorified, that you bear much fruit, and
so prove to be My disciples."
So he is speaking to people who "have been made clean". He is not speaking of those who are not "saved'. He is warning that they MUST abide in him or they cannot bear fruit. Now what sense would it make for him to say "abide in me" if they were never in him. How could they be cut from the vine and BURNED if they were never attached to it? Of course the works that we do are him working in us, producing "thirty, sixty, or 100 fold".
Eph 3
[20]
Now to him who by the power at work within us is able to do far more abundantly than all that we ask or think,
[21] to him be glory in the church and in Christ Jesus to all generations, for ever and ever. Amen.
Any questions?
Blessings